Ordered mesoporous and microporous molecular sieves functionalized with transition metal complexes as catalysts for selective organic transformations.

The use of metal–organic frameworks (MOFs) for the encapsulation of different active entities is thoroughly reviewed. Either by following ship in a bottle or bottle around a ship approaches, active species can be encapsulated in the porous framework of different MOFs. Encapsulated species vary from polymers to organometallics and from polyoxometalates to metal nanoparticles and metal oxides. The main advantages and limitations of the use of MOFs together with the synthetic approaches followed are evaluated.

Metal–organic frameworks as scaffolds for the encapsulation of active species: state of the art and future perspectives

Centro de Quı́mica-Fı́sica Molecular (CQFM) and Institute of Nanosciences and Nanotechnology (IN), Departamento de Engenharia Quı́mica e Biológica, Instituto Superior Técnico, 1049-001 Lisboa, Portugal, REQUIMTE, Departamento de Quı́mica, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, Quinta da Torre, 2829-516 Caparica, Portugal, and iMed.UL, Faculdade de Farmácia da Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal

More sustainable approaches for the synthesis of N-based heterocycles.

Organic synthesis performed through multicomponent reactions is an attractive area of research in organic chemistry. Multicomponent reactions involve more than two starting reagents that couple in an exclusive ordered mode under the same reaction conditions to form a single product which contains the essential parts of the starting materials. Multicomponent reactions are powerful tools in modern drug discovery processes, because they are an important source of molecular diversity, allowing rapid, automated and high throughput generation of organic compounds. This review aims to illustrate progress in a large variety of catalyzed multicomponent reactions performed with acid, base and metal heterogeneous and homogeneous catalysts. Within each type of multicomponent approach, relevant products that can be obtained and their interest for industrial applications are presented.

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Homogeneous and heterogeneous catalysts for multicomponent reactions

12-Molybdophosphoric acid: A recyclable catalyst for the synthesis of Biginelli-type 3,4-dihydropyrimidine-2(1H)-ones

Zeolite-catalyzed cyclocondensation reaction for the selective synthesis of 3,4-dihydropyrimidin-2(1H)-ones

Transition metal ion incorporated MCM-41 has been found to be active for catalytic epoxidation of aromatic olefins ( trans -stilbene) and oxidation of aromatic compound (anthracene). The Cr-MCM-41 catalyst was the best in comparison to the other isomorphously substituted MCM-41. t -Butylhydroperoxide ( t -BHP) has shown better performance at around 80 °C in benzene as a solvent. The highest conversion of 79.3% of anthracene was observed with more than 90% selectivity of the product. Cr-MCM-41 could be used for the reaction without decrease in the catalytic activity.

Liquid phase oxidation of anthracene and trans-stilbene over modified mesoporous (MCM-41) molecular sieves

Immobilization of metalloporphyrin complexes in molecular sieves and their catalytic activity

The macrocyclization reaction of calix(4)pyrroles and porphyrins prepared by zeolite catalyzed synthesis in liquid phase under microwave irradiation conditions was subsequently optimized for quantitative yields. The reactions are carried out with different zeolite catalysts such as HZSM-5, HY and mesoporous Al-MCM-41 molecular sieves and the reactions are monitored by HPTLC for performance evaluation of the catalysts. The present method to synthesize macrocycles, using molecular sieves, such as solid acid catalysts in heterogeneous system, was selective and quantitative. Al-MCM-41 (pore diameter more than 20 A) performs better as to facilitate good selectivity towards quantitative yield and demonstrated excellent conversions when compared to other catalysts.

Synthesis of calixpyrroles and porphyrins over molecular sieve catalysts

FeZSM-5 has been found to be an efficient catalyst for oxidation of cinnamyl alcohol and primary alcohols with high yields and selectivity. Catalyst was reused for several times and was confirmed to be stable without leaching any metal percent into the solvent.

V. Radha Rani

Papers

Zeolite-catalyzed cyclocondensation reaction for the selective synthesis of 3,4-dihydropyrimidin-2(1H)-ones

Liquid phase oxidation of anthracene and trans-stilbene over modified mesoporous (MCM-41) molecular sieves

Immobilization of metalloporphyrin complexes in molecular sieves and their catalytic activity

Synthesis of calixpyrroles and porphyrins over molecular sieve catalysts

Liquid phase selective oxidation of alcohols over modified molecular sieves